Stand- and tree-level determinants of the drought response of Scots pine radial growth

Abstract

Characterizing the responses of key tree species to extreme climatic events may provide important information for predicting future forest responses to increased climatic variability. Here we aimed at determining which tree- and stand-level attributes were more closely associated with the effect of a severe drought on the radial growth of Scots pine, both in terms of immediate impact and recovery after the drought event. Our dataset included tree-ring series from 393 plots located close to the dry limit of the species range. Time series analysis and mixed-effects models were used to study the growth of each tree and its detailed response to a severe drought event that occurred in 1986. Our results showed that the radial growth responses of Scots pine were determined primarily by tree-level characteristics, such as age and previous growth rate, and secondarily by stand basal area and species richness, whereas local climate had a relatively minor effect. Fast-growing trees were more severely affected by the drought and retained proportionally lower growth rates up to three years after the episode. In absolute terms, however, fast-growing trees performed better both during and after the event. Older trees were found to be less resilient to drought. The effect of stand basal area and species richness indicated that competition for resources worsened the effects of drought, and suggested that the effect of interspecific competition may be particularly detrimental during the drought year.

The effects of thinning intensity and tree size on the growth response to annual climate in Cedrus atlantica: a linear mixed modeling approach

“…This result, which we interpreted as the effect of size-related constraints on cedar growth, agrees with a previous study reporting that Pinus with greater growth were proportionally more affected by drought (Martínez-Vilalta et al 2012). The interpretation of this higher sensitivity from the viewpoint of the ability of cedar to cope with drought effects is not straightforward, and we still lack a conceptual framework linking the growth signal features to life traits (Cuny et al 2012) and demography (Martínez-Vilalta et al 2012). Indeed, previous studies produced seemingly contradictory results, reporting higher mortality rates for trees showing highly variable growth (Suarez and Ghermandi 2004) or a weaker correlation between the growth of the dying trees and the climate variables (Linares et al 2010).…”

“…This result, which we interpreted as the effect of size-related constraints on cedar growth, agrees with a previous study reporting that Pinus with greater growth were proportionally more affected by drought (Martínez-Vilalta et al 2012). The interpretation of this higher sensitivity from the viewpoint of the ability of cedar to cope with drought effects is not straightforward, and we still lack a conceptual framework linking the growth signal features to life traits (Cuny et al 2012) and demography (Martínez-Vilalta et al 2012).…”

“…The effect of competition intensity on the climate-growth relationship was often based on experiments that did not reproduce actual silvicultural guidelines: studies were conducted in stands that had not been thinned for decades (Gea-Izquierdo et al 2009;Martínez-Vilalta et al 2012), in stands thinned once (Misson et al 2003) and in stands lightly thinned (Piutti and Cescatti 1997;Timbal 2002;Kohler et al 2010; but see Olivar et al 2013 andSohn et al 2013). As a consequence, several important aspects of management impact on forest functioning were overlooked: (i) the short-and medium-term effects of thinning, (ii) the cumulative effect of successive thinning and (iii) the prospective analysis of the effect of thinning intensities beyond the current guidelines.…”

“…In this approach, the fixed part of the model incorporates the individual growth responses, whereas the random effects represent the hierarchical structure of the data. LMMs have recently been used to standardize tree-ring series (e.g., Martínez-Vilalta et al 2012), but rarely to explicitly quantify the effect of thinning on the climate-growth relationship (Olivar et al 2013).…”

Drought response of upland oak (Quercus L.) species in Appalachian hardwood forests of the southeastern USA

“…and white oak (Quercus alba L.). Beyond interspecific differences in response to drought, drought-growth relationships further vary across age (Copenheaver et al 2011;Martínez-Vilalta et al 2012), tree size (Zang et al 2012;Keyser and Brown 2014), and compositional (Lebourgeois et al 2013) and environmental (Orwig and Abrams 1997;Tardiff et al, 2003;White et al 2011) gradients.…”